An Analysis of the Impacts of Western North Pacific Tropical Cyclones on Their Local and Large Scale Environment

• Other Authors: Schenkel, Benjamin A. (Benjamin Alan), 1984- (authoraut), Hart, Robert E. (professor directing thesis), Dewar, William (university representative), Ellingson, Robert G. (committee member), Cai, Ming (committee member), Clarke, Allan J. (committee member), Department of Earth, Ocean and Atmospheric Sciences (degree granting department), Florida State University (degree granting institution)
• Format: Text
• Language: English
• Published: Tallahassee, Florida: Florida State University 2012
• Subjects: Earth sciences; Oceanography; Atmospheric sciences; Geophysics; Pacific; North Atlantic
• Online Access: https://diginole.lib.fsu.edu/islandora/object/fsu%3A183304/datastream/TN/view/Analysis%20of%20the%20Impacts%20of%20Western%20North%20Pacific%20Tropical%20Cyclones%20on%20Their%20Local%20and%20Large%20Scale%20Environment.jpg

The following study examines the spatiotemporal response of the local scale and large scale environment to tropical cyclone (TC) passage. The research presented here is broken up into three chapters that can be separated into two parts. Given that the analysis of the environmental response to TC passage heavily relies upon the use of atmospheric reanalysis datasets, the first half of this dissertation (Chapter 2) will examine the fidelity of TC intensity, position, and intensity life cycle within five reanalyses to determine what reanalyses can be used for when studying TCs. The results of this analysis show an underestimation of reanalysis TC intensity beyond what can be attributed to the coarse grid resolution of reanalyses. Moreover, the mean life cycle of normalized TC intensity within reanalyses exhibits an underestimation of pre-peak intensification rates as well as a delay in the timing of peak TC intensity relative to the Best Track. Significant discrepancies between reanalysis and Best-Track TC position are noted to exist particularly in regions that are observation deficient. Of the five reanalyses examined, the NCEP Climate Forecast System Reanalysis (CFSR) and JMA 25-yr Japanese Reanalysis (JRA-25) have the most robust representation of TCs particularly within the North Atlantic (NATL) and Western North Pacific (WPAC). The second half of this study examines the local scale (Chapter 3) and large scale (Chapter 4) impacts of WPAC TCs upon their environment using storm-relative composites. On local scales, TCs are found to cool sea surface temperatures (SSTs) for at least a month following TC passage. The feedbacks from the SST cold wake combined with an initial net flux divergence of energy from the column yields a significant cooling and drying of the atmosphere that is strongest in the lower troposphere. Restoration of the environment is eventually achieved through a return of SSTs to climatology and a net flux convergence of potential energy aloft. The large scale response of the environment is ...